Telephone system.



J. ERICKSON.

TELEPHONE SYSTEM. APPLICATION FILED DE C.18,I908- RENEWED MAY 29.1916.

Patented Dec. 26, 1916.

J. ERICKSON.

TELEJ'PHONE SYSTEM. APPLICATION FILED DEC,"18,l908. RENEWED MAY'29.1916.

1209,25. Patented Dec. 26,1916.

5 SHEETS-SHEET 2.

mam /:39; 2 77mm J. ERICKSON.

TELEPHONE SYSTEM.

APPUCATION FILED DEC.18,1908- RENEWED MAY 29.1916.

1 209,825. Patented Dec. 26, 1916.

5 SHEETSSHEET 3- J? a. 7%ZZ.

J. ERICKSUN.

TELEPHONE SYSTEM. APPLICATION FILED DEC. 18, 1908- RENEWED MAY 29.1915.

1,209,25. Patented Dec. 26,1916.

5 SHEETSSHEET 4.

Jx ERICKSON.

TELEPHONE SYSTEM. APPLICATION FILED DEC. 1a, 1908. RENEWED MAY 29.19l6.

1 9,825 Patented Dec. 26, 1916.

5 SHEETSSHEET 5.

%TATE% @FFICE.

JOHN ERICKSON, OF CHICAGO, ILLINOIS, ASSIGNOR TO AUTOMATIC ELECTRICCOMPANY. OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Application filed December 18, 1908, Serial No. 468,141. Renewed May 29,1916. Serial No. 100,702.

To all whom 2'25 may concern Be it known that I, John EmoksoN, a citizenof the United States of America, and resident of Chicago, Cook county,Illinois, have invented a certain new and useful Improvement inTelephone Systems, of which the following is a specification.

My invention relates to automatic or semiautomatic telephone exchangesystems in general. but more particularly to those in which thesubstations are provided with rotary calling dials, and especially tosystems in which the said dials are used for controlling the operationsof switches that have one motion to select groups and another motion toconnect with a line in any selected group, as, for example, selectorsthat have one motion to select groups or divisions of the exchange andanother motion to automatically select an idle trunk line in the groupor division selected by the calling subscriber. or a connector thatoperates in the same manner, except that its second motion is under thecontrol of the calling subscriber to seize or find the called line.

An object of my 'inzvention, broadly speaking, is to provide an improvedarrangement whereby the dial cannot be forced or so manipulated as toaccelerate the impulse-transmitting mechanism, and which will make theproper transmission of the impulses a matter of greater certainty,especially in cases where the subscribers are inclined to be carelessabout the way in which they use the calling dials.

More specifically considered, an object of my invention is to provide acalling dial which can only rotate in one direction, and which isoperatively connected with the impulse-transmitting mechanism. wherebythe dial cannot be forcibly turned backward to unduly accelerate thetransmission of electrical impulses.

Another object is to provide a measuredservice system of such characterthat the calling subscriber is required, by means of improved mechanism,to remove a short-circuit or shunt from around his transmitter, and tothereby register thecall. before he can converse with the calledsubscriber.

' To these and other useful ends my invention consists in mattershereinafter set forth and claimed.

In the accompanying drawings Figure 1 is a front elevation of thekeyboard, show ing the rotary dial. Fig. 2 is a rear elevation of thekeyboard. Fig. 3 is a side View thereof as seen from the right in Fig. 1Fig. 1 is a cross-section on line 4'4 in Fig. 2. Figs. 5, 6, 7, 8, 9,10, 11, 13,14, 15 and 16 are detail views of the keyboard mechanism.Fig. 12 shows a switch-hook spring combination. I 17 is a diagram of thesubstation A comprising a keyboard of the character shown in thepreceding figures. Said substation is connected with automatic switchingapparatus in a central oifice, Said apparatus being of the characterdesigned to be operated by the said keyboard, the said switchingapparatus, as shown, comprising a line switch C, a controlling masterswitch D and a first-selector E, and there being a central battery B forsupplying all operating and talking current.

My improved calling device comprises a dial guard Z upon which there areplaced numbers for aiding the subscribers in selecting the properfinger-hole in the dial 2. The calling device also comprises the usualgovernor gear wheel 4, and switch-hook 5 which controls the switch-hooksprings (Fig. 12) by means of the cam arm 6 2).

In Fig. 4 is shown how the rotatable parts are mounted upon the shaft 7.The dial 2 is secured to the hub S, but the hub in turn is looselymounted upon the shaft 7, so that the dial may be turned withoutrotating the shaft. One end of a coil spring9 engages a slot 10 in thehub 8 (Fig. 8). The other end of this spring is secured to the springbox 11, to which latter is also fastened the impulse wheel ratchet 12.The members 11 and 12 are firmly secured to the shaft 7, and

hence when the ratchet wheel 11 is turned the shaft and all the partssecured thereto are rotated. Also fastened to the dial on the inner sideis the dial ratchet wheel 13. The gear wheel 4, together with theimpulsetransmitting wheel 14, are secured to the hub 15. and the hub 15in turn is rigidly fastened to the shaft 7 by a screw clamp 16. Theshaft 7 carrying all the parts secured thereto. is adapted to rotate inbearings in the front and back plates 17 and 18. The pawl 19, whichcontrols the ratchet wheel 13 (Fig. 9) is pivotally secured to the link20 at the point 21, and the link 20, which is provided with the arm 22,is pivotally mounted on the front plate 17 at the point The specialspring 24 provides the teneion For the parl and arm wr :35, whichpiviited t the poo All. arranged to n5 l. the ratchet .30. hi normalrel: and ratchet 510 there are silo on th e p: i ions "uni-c when theratchet wlicei l3 1.-

tlnfned in the direction indicated by the armor. Since there isspring-coiinection between the dial and ratchet wheel with the wheel 12,there is a tendency for this latter wheel to follow in the direction oithe dial, but this is not permitted by the lever atthis time. In Fig. 11tl'icrc are shown the relative positions these parts as-nuue when thedial is relea When the dial is released the wheel 13, which is rigidwith the dial, due to the tension placed on the spring 9 (Fig. 4), tendsto rotate in a direction opposite "to that indicated in Fig. 10. A tooth27, however, innnediatcly engages the pawl 19 and carrios the latterhack a trifle, thereby moving the pawl l!) and link against the tensionof the spring 2 about the point 23. W hen this occurs the arm 22 pressesagainst the outside lip of, the lever 25, therebj carrying the latterout of engagement with the ratchet wheel 12. The wheel 12 and shaft 7then respond to the tension in the coil spring 9 i) and more in. thedirection indicated by the arrow in Flf; ll. The ilial. ratchet wheel 13remains locked at this time. lfpon the other end of the shaft 7 (asshown in Fig. 4) is mounted the impulse Wheel ll. and gm:- i'vhecl l, asexplained. The impulse wheel 'l-l. in turning; counter-clocliwise (Figs.1:3 and lo}, presses against the spring 98. thus separating the impulsesprings and each time a tooth passes the SPl'l'l When the dial isturned. explai. tho stop screw 1 upon he wh i carried a way from theincu'zbm' 3Q, when. the dial is released the shaft '7' and. all. theparts secured thereto follow or rotate in the same direction as the dialuntil the member 3'2- reaches the stop screw 31 (Fig. 7). The distanceor arc that the stop screw ad- Yancos from the member accurately anddefinitely determined by the finger-holes in the dial. ll licroifiu'c,when the dial is turned for the digit the stop screw 31 is advancedthrough an arc such. that the member 32, in coming to normal position.again, permits the impulse wheel 14: (Fig. 15) to break the normalcontact between the springs 29 and 30 live tin'ics. The gear wheel lengages the pinion of the governor 3, which latter controls the rapiditywith which impulses are transmitted. V

In Figs. 13 and. 14- it will be seen that there are two notches orpositions in the lever 33 for the end of the switch-hook 5. Thisprosubscribers vision is made in order that certain tclc phone circuitsmay be controlled throu h the switch-hook springs. llhcn the receiver isremoved from the switch-hook the end of the latter occiu'iies theposition shown in Fig. lb, and when the dial comes to rest after a digithas been called the switchhooh rests in the position shown in Fig. 14-.This operation is bri'iught aoout as follows: When the receiver isremoved the end the switch-hook rests in the notch 'l-l. Normally.however. before the eeccircr is removed, the switch-hoolcres'is againstthe stop After the dial is turned and then comes to rest," the pawlmechanism, as explained. presses the lever 25 out of engagenient withthe ratchet wheel 1. Also, when this happens the finger 36 upon thelover presses the lever 33 outwardly a trifle (Figs. 11, 13 and 14).thereby permitting the switch-hook 5 to fall to the notch 3?.

In the foregoing the mechanical construction and arrangement of thedifferent parts of my calling device have been explained. It will now bepointed out how the calling device may be used in connection with atelephone for operating the switches of an automatic central. ollice.shown in Fig. 17, the substation Av coinprises, in addition to thecalling device, the receiver 38, ringer 39 in series with the con denser40, an induction coil 41 comprising the primary winding and secondarywinding 43, and a transi'nitter 44.

In Figs. 12 and 17 the switch-hiioli spring combination is arranged forthe operation of meter or registering device at the telephone. If themeter or registering device is not used, then the two lower 'lllflS 5%and are not used. and the switch-hook spring; combination is the same asshown in Figs. l. 9 and 3. In addition there is shown a meter orregistering mechanism. cons'slw inn o? the paslrbutton l?) which when.pressed, discngagrs the springs 46 and *i? and also moves the ratchetwheel 48 of the motor 4.9 one step; Furthermore, when the button is thusoperated the pawl 50 falls over the end of the spring 47 and locks thelatter in its operated position until the receircr is restored to theswitch-hook, thereby unlocking'the push-button spring when the rod 51engages the pawl 50. The line conductors 52 and 5301 the substation Aterminate in the line switch C, which is of the general type of lineswitch disclosed in English Patent No. 26,30l of 1906, and in the West/11m Electrician published at Chicago, Illinois, U. S. A, January 25,1908. The controlling master switch D is also disclosed in the abovereferences. The selector switch E is of the general type of selectorswitch. shown in United States Letters Patent No. 815,321. issued toKeith, Erickson and Erickson March 13, 1906. As shown in Fig. 17, all ofthe switches and the telephone A are wired with circuits such that theywill operate on a two-wire s \'stemthat is, there is no operating groundat the subscribeus station, the impulses being made by opening andclosing the two line conductors in series, so that the groundconnections are employed at the central otiice only. \Vhen thesubscriber removes the receiver 88 from the switch-hook 5 the springs 51and 55 engage and the springs 50 and 57 disengage. The spring 57,however, does notcngagc the spring 58 until the dial is turned, when theswitch-hook 5 engages the lower notch 37 (Fig. 14) as explained. Theengagement of the springs 51 and 55 closes an energizing circuittin-ough the trip magnet 59 ot' the line switch C. This circuit extendsfrom ground G at the line switch through the trip magnet 59,bridge-cut-ott' springs 60 and 01 to the line conductor 53, through theprimary winding 42, transmitter H, springs 55 and 54, impulse springs 29and 30 to the conductor 52, bridge-cut-ott springs 62 and 63, resistancecoil 641 to the battery lead 05, thence through battery B to ground G.The trip magnet 59, upon energizing, attracts its armature and permitsthe plunger to engage an idle bank terminal, thereby pressing thesprings 66 and 67, 68 and GE) 70 and 71, and 79 and 73 into contact. Theengagement of the springs 70 and 71 estab lishes and energizing circuitthrough the bridge-cut-otl' relay 7 1 which operates to disconnect theline conductors 52 and 53 from the line switch connections. Also, whenthe springs 7 0 and 71 engage, then a positive guarding potential. isestablished over the conductor 75 at the connector private bank contactcorresponding to the line of substation A. The engagement ofthe banksprings 68 and 69 closes a. energizing circuit through the motor magnetrelay 76 of the master switch D. This circuit extends from ground Gthrough the winding 77 to the common segment 78 of the master switchbank wiper 79, to the individual contact SO (assuming that this contactcorresponds to the bank terminal just engaged by the line switch C),conductor 90, bank springs 69 and 68, winding of the release magnet 91to the battery lead 65, thence through battery B to ground G. Althoughthis circuit includes the windings of the release magnet, the saidmagnet does not. operatively energize, since the winding 77 of the relay76 is of such comparatively high resistance that a very small current isflowing. The relay 76, upon energizing, presses the springs 92 and 93into contact, thereby closing an energizing circuit through the motormagnet '94 extending from ground G through the springs 92 and 93,interrupter spring 95, motor magnet 94 to the battery lead 65, thencethrough battery B to ground (1. The motor magnet energizes and operatesthe ratchet wheel 00 one step, assuming the next trnnh'.line is idle,whereby the shall 07 carries the idle plungers opposite the next idlebank terminal and the wiper 70 into engagement with the imlividualcontact corresponding to the idle trunk. The cngagcment ol' the banksprings 06 and 0? and T2 and '73 extends the substation line conductors52 and 53 to the trunk line conductors 0S and 90, respectively, whichlead to the selector switch 10. An energizing circuit is immediatelyclosed through the line relay 100 extending from ground G through thewinding 101, side switch wiper 102, conductors 00 and 53, through thesubstation to the conductors 52 and 98, side switch wiper 103, winding101. to the battery lead 05, thence through battery B to ground G. Thisline relay energizes and separates the spring 105 from the spring 106,and closes the springs 105 and 107 in contact. The engagement of thelatter springs closes an energizing circuit through the slow-actingrelease relay 108 which operates to in turn carry the spring 109 out ofengagement with the spring 110 and into engagement with the spring 111.The line relay 100 remains in this energized position as long as theline at the substation is closed, but when the dial is rotated, and inturn the impulse. wheel 11, the impulse springs 29 and. 30 are thenseparated momentarily, thereby intermittently breaking the energizingcircuit of the line relay 100. The deenergizing of the line relay 100permits the spring 105 to engage the spring 100, thus closing acircuitthrough thew'crtical magnet 112. This circuit extends from groundG through the springs 105 and 106, springs 109 and 111, private magnetrelay 113, vertical magnet 112, side switch wiper 114 to the batterylead 65, thence through battery 13 to ground G. The vertical magnetenergizes and operates to carry the shaft wipers 115, 116 and 117 in avertical direction one step at a time for each impulse. Since thevertical magnet circuit includes the private magnet relay 113, it alsoener-- gizes and places the springs 11S and 119 in contact, therebyclosing a circuit through the private magnet 120 from ground G Theprivate magnet relay 118 energizes {upon the first vertical impulse tothe vertical magnet and, being slow-acting, remains in this energizedposition until all of the vertical impulses are set, and then, since theenergizing circuit is no longer maintained, the relay 113 restores tonormal position, breaking the energizing circuit for the private magnet120 which operates to pass the side switch to second position. The sideswitch wiper 114, upon passing to second position, closes an energizingcircuit through the retary magnet 121 which operates in the usual Irelay 128 of the switch F in the same man-- 125. When the side switchwipers 103 and 102 pass to third position the line conductors 52 and 53are extended to the shaft wipers 115 and 116, respectively, and to tl etrunk conductors 126 and 127, thereby closing an energizing circuitthrough the line nor in which the circuit was closed through the linerelay 100 of the switch E. The calling subscriber may operate the linerelay 128 of the switch F in accordance with the next digit of thedesired number. After having operated the dial for each digit andestablished connection with the desired line, the two subscribers maycarry on communication. The subscriber at substation A, however, beforehe can successfully talk with the called party, must press the button45, thereby separating the springs 46 and 47 and operating the meter onestep, as explained. It will be seen that before the meter button ispressed there is a shunt around the transmitter 44 through the springs58 and 57 to the spring 54. The calling subscriber, moreover, may hearthe called party answer, but before the calling subscriber can reply,the transmitter shunt must be removed by pressing the button whichregisters the call. The meter mechanism, when once operated, re mains inits operated. position until the calling subscriber restores hisreceiver to the switch-hook and thereby unlocks the locking pawl 50. Therestoration of the central office switching apparatus occurs when thecalling subscriber restores his receiver to the switchhook and opens theenergizing circuit for the line relay of the connector switch. The linerelay, upon deiinergizing, breaks the energizing circuit for theslow-acting release relay, which in turn also falls back, therebyremoving the ground potential from the private bank contact engaged bythe private wiper 117. The removal of this ground also breaks theenergizing circuit of the slowacting relay 108 of the selector E. Thisrelay then falls back, placing the spring 109 in contact with the spring110, thereby cl0sing an energizing circuit through the release magnet125 extending from ground G through the springs 105 and 106, springs 109and 110, through the release magnet 125, normal springs 124 and 123 tothe battery lead 65, thence through battery B "to ground Gr. The releasemagnet, upon energizing, restores the switch shaft and side switch tonormal position. i/Vhen the switch shaft roaches normal position thenormal armlQPi upon. the shaft carries the normal springs 123 and 124out of engagement, thereby tweaking the energizing circuit for the remagnet. The release magnet, when enzed, holds the springs 129 and 180 incontact, thus closingthe energizing circuit for the release magnet 91 ofthe line switch C. The release magnet 91 energizes and opcrates therelease mechanism to withdraw the plunger from the bank terminal andpermit the bank springs to restore. to normal position. At thesubscribers station, when the receiver is restored, the switch hooksprings return to normal position; also, the rod 51 presses the pawl 50so that the meter button springs return to normal position.

From the foregoing it will. be seen that there is no normal position forthe dial and the impulse wheelthat is, the dial is r0- tated in onedirection only, also the impulse wheel. Whenthe dial is turned for anynumber, tension is placed in the dial coil spring. This tension istransmitted to the shaft, but the shaft is preventedfrom turning untilthe dial comes to rest. when a lever which holds the shaft locked isremoved. The shaft being free then responds to the spring tension androtates'in the same direc tion that the dial was previously turned. Thenumber of impulses transmitted is determined by the are through whichthe dial is turned-that is, the impulse wheel, in response to the springtension of the dial springs, rotates through an equal are. It will beseen. that the switch-hook 5 is permitted to pass from tne positionshown in Fig. 13 to the position shown in Fig. 14 by the action of thelever 25. This iever 25, by being pressed away from the gear 12, asshown in Fig. 11, through the medium of the pin 36, presses the catchaway from the switchhook 5, thus permitting the said switch-hook to passfrom one position to the other.

In the foregoing reference has been made to connector switches. Itshould, therefore, be stated that connector switches with which theselector E is adapted to establish connection for completing the circuitbetween the calling and called subscribers are of'the general typedisclosed in United States Letters Patent No. 815,176, issued Viarch 13,1906, to Keith, Erickson and Erickson. More particularly, however, theconnector switches in this system are adapted to the particularcharacter of system and. circuits herein disclosed.

It wili be seen that I provide a rotary impulse wheel and a rotarycalling dial operatively connected together in such manner that the dialrotates first and the impulse wheel afterward, the rotation of the wheelalways being coextensive with and determined by the rotation of thedial. The dial is rotated for the different digits of the called number,and at the end of each rotation the impulse wheel is released andallowed to catch up with. the dial-that is to say, the wheel and thedial are always normally in the same relation to each other,notwithstanding that the dial is rotatable while the wheel is standingstill. The dial and the wheel rotate successively, one after the other,and the rotation of the wheel always corresponds in degree to therotation of the dial. The dial rotates ahead, drawing away from thewheel, so to speak, but as soon as it stops the wheel is then releasedand allowed to catch up and regain its normal position relative to thedial. Thus the dial and the wheel rotate always in the same direction,the dial rotating first and the wheel afterward, the release of thewheel being effected by a very slight back rotation of the dial.Obviously, however, the dial is never rotated backward to an extent tobring it to its normal position. In view of its continuous rotationalways in the same direction the dial is, therefore, provided with anendless series of finger-holes adapted to be used in the mannerdescribed. It will also be seen that the calling subscriber, afterestablishing connection through the automatic apparatus to the calledline, cannot then converse with the called subscriber until after he hasremoved a short-circuit or shunt from around his transmitter. When thecalling subscriber does this he at the same time registers the call, orcollects the coin or check. For the broader purposes of my invention themeasured-service device may be of any suitable character that is to say,it may be a coin or check controlled mechanism or a call-registeringdevice of any suitable, known or approved character. Whatever it may be,however, the use of the calling subscribers transmitter to converse withthe called subscriber is contingent upon the operation of such device.

What I claim as my invention is:

1. In a calling device, an electrical impulse-transmitting mechanism, arotatable dial connected for operating said mechanism, means forpermitting the dial tonotate backward only a portion of its forwardrotation, and means governed by the said limited backward rotation ofthe dial for causing the said mechanism to transmit the impulses.

2. In a calling device, an electrical im pulse-transmitting mechanism,'adial rotatable to cause the operation of said mechanism, and means forpreventing said dial from returning to normal position, the latterhaving an impulse wheel rotatable only in one direction.

3. In a calling device,-a rotary impulse wheel, a calling dial connectedfor operating said wheel to transmit a plurality of series of impulses,means for preventing said dial from returning to normal position duringsaid operation, means operative to cause the wheel to rotate in the samedirection as the dial. after the latter has reached the, limit of itsrotation, and means for limiting the rotation of the wheel to thedistance traveled by the dial, whereby the dial rotates first and thewheel u'l'terwurd in the same direction.

l. In a calling device, a rotary impulse, wheel rotatable in but ondirection, a calling dial ha ringno normal position, a spring arrangcdto be. placed under tension by the. forwardrotation ol the dial, andmeans for then permitting said spring to rotate the wheel in the same.forward direction when the dialis released.

5. In a. calling device, a manually-operated dial and an impulse wheelrotatable only in one direction, a spring for rotating the wheel adistance each time equal to the forward rotation of the dial, means forholding said wheel against rotation, and means for autonmticallyreleasing the wheel when the dial is released, whereby the dial andwheel always rotate successively and in the same direction.

6. In a calling device, an electrical impulse-transmitting mechanismrotatable in but one direction, a dial connected for operating saidmechanism, and means for preventing said dial from rotatively returningto normal position when rotated forward to operate the said mechanism.

7. In a calling device, an electrical impulse-transmitting mechanismrotatable in but one direction, a rotatable dial connected for operatingsaid mechanism, means for permitting the dial to rotate backward only aportion of its forward rotation, and means governed by the said limitedbackward rotation of the dial for causing the said mechanism to transmitthe impulses.

8. In a calling device, an electrical impulse-transmitting mechanism, adial rotatable to cause the operation of said mechanism, and means forpreventing said dial from returning to normal position, the latterhaving an impulse wheel rotatable only in one direction, said dialincluding an endless ,series of finger holes.

91 In a calling device, an electrical impulse-transmitting mechanismcomprising an impulse wheel, a dial connected for operating said Wheel,said wheel rotatable in but one direction, means whereby a plurality ofsuccessive operations of said dial will operate said impulse wheel totransmit a plurality of series of impulses, and means for preventingsaid dial from returning to normal position during said operation.

10. In a calling device, a dial, an impulse Wheel, a spring for rotatingthe wheel a distance each time upon the forward rotaulse wheel zwainstrotation and means h 3 CODlZl'OllQCl by the clial for releasing saidwheel, whereby the dial and wheel rotate successively.

11. in a calling de -doe a dial, an im- Jig the wheel with the saidpulse wheel a spring for rotnr J {L variable distance in accordancerotation oi the dial, Trv ans for loi .1 impulse wheel against 2.tution, anvil controlled by the dial for releneing Szi'lC; wheel,whereby the dial and. wheel rotate successively.

12, In it calling device, an impulse transmitter comprising a tllill andmi impulse wheel, the dial having no normal position, a spring forrotating the impulse Wheel a distance in accordance with the variableforward rotations of the dial menus for locking said impulse wheelagainst rotation, and means controlled by tlie'a'linl for releaeing theimpulse wheel.

13. in a calling device :1 tlial provided with continuous line of lingerholds an tion, connecting means he wheel and the dial for rotating theWheel a :listance each time upon the fox-weal rotation of the (ligilmeans for locking the impulse wheel against rotation, uncl meanscontrolled by the dial for releasing the impulse wheel. v

Signed b me at Ch. Cool; county, lllizio' this 8 Joy of 1908.

Jo nt iieioireoit

